Eotvos&#39;s torsion balance



s. RYBAR Bb'Tvb's s TORSION BALANCE Nov. 3, 1931.

Filed March 20, 1926 2 SheetsSheet 1 Fig.2.

jaw [7'24 giafimw v Patented Nov. 3, 1931 s'rnrnnn RYBAR, or nunarns'r, HUNGARY norvos's TORSION BALANCE Application filed March 20, 1926, Serial No. 96,360, and in Hungary latch 23, 1925.

My invention relates to Eotvoss torsion balance and has for its object to enable the dimensions of the balance and more especially its height to be considerably reduced without the sensitiveness of the balance being thereby lessened to any extent whatever.

The torsion-balance according to my invention isdiagrammatically shown in the accompanying drawings in two difl'erent em- 1o bodiments.

Figs. 1 and 2 are vertical sectional views of one embodiment taken in two planes at right angles, while Figs. 3 and 4 are similar views of a modification. 15 c From the measuring wires 1 are suspended the pendulum-arms, 2, from which are suspended the weights 3 by means of filaments 4. The other weights 5 are 'fastened to the end of the pendulum-arms 2 and there are also arranged in connection with the latter mirrors 6. v

The sources of light, for example incandescent lamps 9, which produce the light signals that constitute the result of the measurement are arranged at the bottom 8 of the casing 7 of the instrument and the light rays 10 are directed to the prisms 11 arranged opposite the mirrors 6 and from the reflecting surface of these prisms on to the mirrors 6. The light rays reflected by the mirrors 6 enter the prisms 11,wherefrom they are pro.- jected again in the downward direction toward the bottom 8 and through the opening 12 provided therein they are thrown on to a 55 photographic late placed on a supporting plate 13 on whlch the rays produce, in a wellv own manner light signals which are afterwards fixed.

In the manufacture of an Eotvos torsion- I=0 balance the latest efiorts are being directed towards producing a balance of small dimen-' sions. This end may be best accomplished by a reduction of the length of the measuring wires 1. If, however, the length of the measuring wires 1 is reduced from approximately 56 centimeters which is the length hitherto used to about 15 centimeters, and the hitherto usual arrangement-of the register plates, at the upper part of the instrument is pre- 0 served there willnot remain sufiicient room for the light rays, while with the construction above described suflicie'nt room remains between the mirrors 6 and the registering apparatus even when the instrument is of small height to allow the light rays to be sufficiently lon I for attaining the desired sensitiveness. ince the light rays from the light sources striking the mirrors 6 have a constant direction and only those rays reflected by the mirrors 6 on to the registering apparatus are deflected because of the swinging of the mirrors, it is evident that the location of the light sources is of no importance from the inventions point of view so that these light sources maybe arranged in any convenient manner, for instance sideways or above, in which case the rays of the light sources will have to be projected on to the mIIIOIS 6 through a suitable arrangement of prisms.

From the inventions point of view, it is 7 only essential that the registering apparatus or the sensitive plate receiving the light signals, should be arranged under the pendulum because this space may always be formed in sucha manner as to permit the registering .75 rays to have the required length.

In arranging thesensitive plate I do not restrict myself to the bottom of the casing of the instrument since I may arrange the plate still deeper. A

While in the embodimentshown in Figs. 1 and 2 the light sources are the two vertical planes passing through the two pendulums and thus the prisms 11 lie between those pendulums in the modification shown in Figs.

.3 and 4, the light sources and the prisms are arranged outside the two pendulums, in which case, of course, two separate supporting plates 13 will be required for holding the photographical plates. This latter arrangement has the advantage as compared with the former that in the center part of the instrument a well proportioned journal of rotation or standard 14 may be arranged which enables the casing of the instrument to '95 .be accurately journalled.

I claim:

In an Eotvos torsion balance, the combination of a measuring wire with a pendulumarm suspended from said wire, a filament fixed to one end of ,said pendulum-arm, a weight su ended from said filament, a weight fixe to the other end of said penduhim-arm, a mirror connected to the pendulum-arm, a prism adapted to cooperate with said mirror, a light a source for throwing light rays onto said prism and said mirror, and a support for a. photographic plate below said pendulum-arm for receiving light rays projected by said mirror through said prism, the light source and. recording apparatus being arranged outside ,the plane passin through the pendulum-arm.

In testimony whereof I have hereunto affixed my signature.

DB. STEPHEN RYBAB. 

